Need to rewrite format of "check_networks" result attribute

Now we have the following output format of 'check_networks' task result attribute:
{error: ['cidr', 'gateway'], ids: [1,2,..]}, where 'ids' are invalid network ids (empty list in case of networking parameters error), 'error' list contains names of invalid fields.

Due to such structure:
1. it's impossible to display networking parameters errors on UI;
2. it's impossible to distinguish what fields from an 'error' list are invalid for the specific network.

So, to solve these problems I suggest to rewrite task result output format in this way:
{networks: {<network_id>: [<network_attribute>, ...] }, networking_parameters: [<networking_parameters_attribute>, ...]}